With the last news that was found a
vulnerability in the
Ethereum DAO the coin lost almost 50% of its value in 2 days. Do you think is still worthy buy
I would say that depends on the risk somebody is willing to take.
Buying is always a risk as any coin (real or crypto) can always loose some or all of its value. Therfore past spent cost should never be the trigger for a decision, only future expectations are really relevant here.
The current issue got identified in the DAO contract code and not in the code of Ether(ium) and it is not clear yet what the following steps (risk mitigations like loss sharing, code changes, soft and/or hard fork, ...) between Etherium, miners, investors, the attacker, .... will be, so there is quite some insecurity at the moment.
As The DAO contract is deeply linked to Ether (and there is not a lot more linked to that coin by now) it for sure influences the short term value of Ether, so from that point of view it might be a good time (soon) for a cheap buy with a (DAO related) higher risk.
Learning from Bitcoin: Over a longer term fixed past issues have a positive effect on the overall system, its security and the coin value, so buying later can become more expensive due to some added value that can be called a (more or less significant) lower risk.
Finally only time will tell (also if the DAO will survive somehow).